The above-mentioned indene-3-acetic acid is a known compound having anti-inflammatory activity as described in U.S. Pat. No. 3,654,349. The compound has been prepared by a number of methods as disclosed in the above-mentioned patent as well as U.S. Pat. No. 3,732,292 issued May 8, 1973 and U.S. application Ser. No. 33,972 filed May 1, 1970, now abandoned. In one of the methods described in U.S. Pat. No. 3,732,292, 5-fluoro-2-methyl-1-(p-methylsulfinylbenzyl)-indene is disclosed as an intermediate. This intermediate is reacted with a glycolic acid ester and the product is subsequently oxidized to the ester of 5-fluoro-2-methyl-1-(p-methylsulfinylbenzyl)-indenylidene-3-acetic acid which is then isomerized and hydrolyzed to achieve the desired compound. Also in U.S. Ser. No. 33,972, the preparation of the indanone intermediate of this invention is described for the preparation of the indene starting material therein. The preparation of said indanone, however, is quite different from the present preparation and involves reacting 3-nitrobenzaldehyde with propionic anhydride to form the appropriate nitrocinnamic acid, reducing said compound to the corresponding amino compound and further reaction to form the .alpha.-methyl-3-fluorohydrocinnamic acid. This compound, in turn, is cyclized to form the indanone.
It is an object of this invention to provide new processes for preparing 5-fluoro-2-methyl-1-(p-methylsulfinylbenzylidene)-indene-3-acetic acid. It is a further object to prepare this compound via new processes which are advantageous over the process described above. It is still a further object to prepare the intermediate indanone in a much shorter path, with higher yields than previously described.